Peristaltic pump having a roller support

ABSTRACT

The rollers of a peristaltic pump are supported to prevent said rollers from compressing said tube more than the thickness of the walls of the tube. A tube holder rotates along with the roller assembly of the peristaltic pump and keeps the tube in line with the rollers.

RELATED CASES

This application is a continuation-in-part of U.S. application Ser. No.08/387,595, now U.S. Pat. No. 5,576,503, filed Feb. 13, 1995, which is acontinuation-in-part of U.S. application Ser. No. 08/120,724, filed Sep.13, 1993, now abandoned, which is a divisional application of U.S.application Ser. No. 07/807,200, filed Dec. 16, 1991, now U.S. Pat. No.5,401,139, which is a divisional of U.S. application Ser. No. 07/474,154filed Feb. 2, 1990, now U.S. Pat. No. 5,125,801 in the names ofFrederick Alan Nabity, Paul George Wright, Raymond Hulinsky and DouglasTimothy Carson for PUMPING SYSTEM and assigned to the same assignee asthis application.

BACKGROUND OF THE INVENTION

This invention relates to pumping systems and more particularly topumping systems that draw samples from a source of liquid.

It is known from U.S. Pat. No. 4,415,011 to Douglas M. Grant, issuedNov. 15, 1983, and from U.S. Pat. No. 4,660,607 to Carl D. Griffith,issued Apr. 28, 1987, to pump liquids from a liquid source through aperistaltic pump into sample containers. In such system, the liquid ispumped through a flexible tube, the location of the liquid in the tubeis sensed and it is metered into sample containers. The tube issubjected to flexing by rollers at a rate intended to deposit apredetermined sample volume into preprogrammed containers arranged in asample tub. A distributor may move a nozzle over the appropriate samplebottle to deposit the sample therein. The distributors usually followone predetermined path.

In the, prior art samplers of this type, the peristaltic pumps aregenerally mounted horizontally with a horizontal axis of rotation forthe roller assembly and fasteners such as bolts or screws must beremoved to obtain access to the interior of the pump. The distributoronly follows a continuous path and stops at mechanically fixed positionsto deposit samples. Equipment used for triggering the taking of samplessuch as flow meters in stand alone equipment for such measurements.

These prior art samplers have several disadvantages such as for example:(1) under some circumstances, the tubes may travel laterally out ofposition within the peristaltic pump, resulting in a decrease inefficiency and increase in wear on the tube; (2) the pump may be unableto pump at the desired flow rate when there is a large head of pressure;(3) the tube within the pump may be subject to excessive wear; (4) it isdifficult to change the peristaltic pump tube; (5) there may beoccasions in which the outlet port of the sampler does not align in asatisfactory manner with the container to provide liquid therein; (6)there is insufficient flexibility in the movement of the distributor;(7) the samples may under some circumstances be tampered with to avoiddetection of of some water conditions; and (8) the equipment used incooperation with the sampler is excessively bulky and expensive.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the invention to provide a novel liquidsampler.

It is a further object of the invention to provide a novel pumpingsystem.

It is a still further object of the invention to provide a pumpingtechnique which provides higher average line velocity under a head ofpressure.

It is a still further object of the invention to provide a pumpingsystem that permits easy changing of tubes;

It is a still further object of the invention to provide a peristalticpump in which the tubes within the peristaltic pump have a longer life;

It is a still further object of the invention to provide a sampler whichis able to deposit samples at random time intervals in containers inorder to avoid tampering;

It is a still further object of the invention to provide a samplerhaving a distributor for distributing samples into bottles in which theresolution of the position of the distributor is accurately programmablycontrollable;

It is a still further object of the invention to provide a sampler inwhich different modules such as bubbler modules or data processingmodules may be attached;

It is a still further object of the invention to provide a novelsampling technique in which better registration of the outlet nozzlewith the sample container is provided.

In accordance with the above and further objects of the invention, asampler includes: (1) a peristaltic pump that is mounted horizontallywith a vertical axis of rotation of the roller assemby for easyinsertion of pump tubing, has a tube aligning system to reduce creepingand peristaltic pump tube wear, a pump tube through which liquid isdrawn at a higher average velocity, particularly when the speed ofpumping cooperates with the pump tubing energy of restoration; (2) adistributor that has improved registration with containers to receivesamples from the pump; and (3) is able to deposit samples in bottleshaving random time, intervals under program control for securityreasons.

The peristaltic pump housing is mounted to rotate the rollers in ahorizontal plane about a vertical axis. One side of the pump housing isopened easily to expose the rollers for easy insertion of tubing. Therollers are designed with guides to avoid moving the tubing out ofposition and in one embodiment, are spring biased against a platen toavoid crushing the tubing. A safety check is provided by a magnet andreed switch to prevent the pump motor from operation when the pumphousing is open.

The tubes are specially constructed to cooperate with the pump motor formaximum efficiency by utilizing a speed and energy of restoration thatmaximizes vacuum force on the liquid. For this purpose, the hose isspecially cured for stability and a thickness is selected to provide acoefficient of restoration that increases the vacuum pressure. The pumpis operated at a speed in which the energy of restoration is sufficientto restore the shape of the tube between compression at relatively highspeed and may pull water under a twenty-four foot head with a velocityof two feet per second. The housing accommodates modules connected tosensors for transmitting sensed values and for recording them.

In operation, the nozzle of the distributor is adjustable in positionand may be programmed with precision to register with bottles ofdifferent sizes and at different locations. For zeroing, the distributoris moved in a first direction against a stop and then rotated in theopposite direction to press against the stop from the opposite side. Theplay between the two caused by pressure against the stop is measured andutilized to provide a zeroing function from the distributor and thuspermit greater accuracy during distribution. The distributor includes acoded pulse generator that generates pulses in accordance with itsmovement among the bottles to have in memory an exact indication ofwhere it is located. In that manner, the program may control thelocation of the outlet of the distributor hose to time the depositing ofsamples even though different arrangements of bottles may be used in thesame container.

The sampler includes a random number generator so that samples will betaken at random times. The pattern is stored in memory. This preventstampering with sample times by personnel working at a site in whichmonitoring is taking place. Standard bottles with standard samples maybe included so that, if tampering occurs with the sample bottles, it maybe detected by interrogating the memory to determine when samples weredrawn from the body of water and into which containers they weredeposited and which samples or sample bottles should have standardsolutions or no solutions in them. Moreover, the software can be drawingand inserting one set of samples in containers according to one programand nonetheless simultaneously follow at least one other program. Theother program or programs may be triggered during the first to startprogram such as by the detection of a programmed pH or flow rate.

From the above description, it can be understood that the pumping systemof this invention has several advantages, such as for example: (1) itpermits higher average pumping velocities under high head conditionswith peristaltic pumps; (2) it provides longer life to peristaltic pumptubes; (3) it increases the life of tubes and reduces lateral movement;(4) it permits more precise positioning of the distributor outlet port;(5) it permits easy attachment of modules for cooperation with thesampler; (6) it permits safe and easy access to the pump tube forreplacement thereof; and (7) it provides a security system to avoidtampering with samples.

SUMMARY OF THE DRAWINGS

The above noted and other features of the invention will be betterunderstood from the following detailed description when considered withreference to the accompanying drawings, in which:

FIG. 1 is a block diagram of a pumping system in accordance with theinvention;

FIG. 2 is an exploded perspective view of a sample collector using thepumping system of FIG. 1 in accordance with an embodiment of theinvention;

FIG. 3 is a partially exploded, perspective view of a liquid sensingdevice used in the embodiment of the invention shown in FIG. 1;

FIG. 4 is an exploded perspective view of a liquid sensing device usedin the embodiment the invention shown in FIG. 1;

FIG. 5 is an elevational sectional view of a portion of a liquid sensingdevice used in the embodiment of the invention shown in FIG. 3;

FIG. 6 is a fragmentary, exploded perspective view of the liquid sensingdevice and pumping system used in the embodiment of the invention shownin FIG. 1;

FIG. 7 is a fragmentary simplified perspective view of an embodiment ofa sampler broken away to show a distributor and a bottle tub useful inthe embodiment of FIG. 2;

FIG. 8 is an exploded fragmentary perspective view of a pump, sensingsection and distributor useful in the embodiment of FIG. 2;

FIG. 9 is a fragmentary top elevational view of a portion of the sensingsection of FIG. 8;

FIG. 10 is a simplified, fragmentary perspective view of a pump rollerassembly in accordance with the invention;

FIG. 11 is a simplified perspective view of an embodiment of pump andsensing system;

FIGS. 12 and 13 are simplified fragmentary perspective views of twoother embodiments of pumping systems;

FIG. 14 is a schematic drawing of an air bubbler module in accordancewith the invention;

FIG. 15 is a schematic diagram of the container full detection system;

FIG. 16 is a block diagram of a portion of the pumping system of FIG. 1;

FIG. 17 is a block diagram of a portion of one of the embodiment of FIG.16;

FIG. 18 is a flow diagram of a portion of a program used to operate thesampler of FIG. 2;

FIG. 19 is a flow diagram of a portion of the embodiment of FIG. 18;

FIG. 20 is a flow diagram of still another portion of the embodiment ofFIG. 18;

FIG. 21 is a block diagram of still another portion of the embodiment ofFIG. 18;

FIG. 22 is a block diagram of another portion of the program of FIG. 18;

FIG. 23 is a flow diagram of a portion of still another embodiment theprogram of FIG. 18;

FIG. 24 is a flow diagram of a portion of the program segment of FIG.18;

FIG. 25 is a block diagram of still another portion of the embodiment ofFIG. 8;

FIG. 26 is a block diagram of another embodiment of FIG. 18;

FIG. 27 is a flow diagram of another portion of the embodiment of FIG.18;

FIG. 28 is a block diagram of another portion of the sampler of FIG. 2;and

FIG. 29 is a block diagram of still another program useful in theembodiment of FIG. 2.

DETAILED DESCRIPTION

In FIG. 1, there is shown a block diagram of a pumping system 10 havinga flow measurement and control circuit 12, a pulse sensor assembly 14, aperistaltic pump 16, a cycle signal generator 11 for generating signalsindicating the cycles of the pump, a sample collector 18 and a conduit20. The conduit 20 is fastened to and communicates with an inletstraining device 22 and extends through the pulse sensor assembly 14,the peristaltic pump assembly 16 and the sample collector 18 into whichit supplies liquid.

The flow measurement and control circuit 12 is electrically connected tothe pulse sensor assembly 14 to receive signals therefrom indicatingpumping cycles of liquid after the liquid has reached a specificlocation and to control the peristaltic pump assembly 16 and samplecollector 18 to deposit predetermined volumes of liquid into a samplecontainer or a group of sample containers in accordance with apreprogrammed procedure or under the manual control of an operator.

The cycle signal generator 11 is connected to the rotor of theperistaltic pump in the peristaltic pump assembly 16 and generates apredetermined number of pulses for each cycle. These pulses aretransmitted to the flow measurement and control circuit 12 through aconductor 13 to provide an indication of pump cycles and throughconductor 15 to indicate the direction of rotation (necessary only inone embodiment) for use in controlling the peristaltic pump assembly 16in a manner to be described hereinafter.

The conduit 20, inlet strainer 22, peristaltic pump assembly 16 andsample collector 18 may be of any suitable type. A similar arrangementis disclosed in U.S. Pat. No. 4,415,011 except that the samplecollecting arrangement of U.S. Pat. No. 4,415,011 utilizes a differenttype of pulse sensor and relies for control of the volume of liquid on adifferent circuit arrangement and program. Nonetheless, many differentcontrol circuits and different types of pumps which produce pulses whenthey are pumping, types of sample collector 18, inlet strainer 22 orconduit 20 may be used in the invention.

In use, the inlet strainer 22 is inserted in the liquid 24, samples ofwhich are to be drawn and data such as the amount of fluid. for eachsample, the time between samples, the size of the conduit 20 and thelike are entered through a keyboard. The peristaltic pump assembly 16 isstarted under the control of the flow measurement and control circuit 12and begins pumping liquid. As it pumps liquid, there is some forceapplied to the flexible conduit 20 as the liquid 24 begins to moveupwardly through the pulse sensor assembly 14 into the peristaltic pumpassembly 16.

The pulse sensor assembly 14 senses pulses, and for this purpose is, inthe preferred embodiment, a piezoelectric film contacting the conduit tosense expansion of the conduit. A suitable type of film is availablefrom the Kynar Piezo Film Sensor Division of Pennwalt Corporation havingan office at 950 Forage Avenue, Norristown, Pa. 19403. This film isdescribed in a booklet entitled "Piezoelectric Film Sensors AnIntroduction to the Techology", by Douglas Kehrhahn, available fromPennwalt Corporation, Piezo Film Sensor Division, P.O. Box 799, ValleyForge, Pa. 19482.

Because the pulsations from the peristaltic pump assembly 16 areabsorbed by air in the conduit 20 until the liquid reaches theperistaltic pump assembly 16, the pulses received by the pulse sensorassembly 14 do not cross a predetermined amplitude threshold until theliquid reaches a predetermined location. This predetermined locationdepends on the size of the head and the amount of the liquid beingpumped. The greater the head, the closer the predetermined location isto the pump. It is possible to locate the sensor directly at the pump orafter (downstream of) the pump and this will change the location of thepredetermined point. Data in the lookup table must be adapted to thischange in location of the sensor.

With this arrangement, the pulse sensor assembly 14 senses pulseamplitude and determines the interface of pulses and applies the signalto the flow measurement and control circuit 12 indicating that theliquid has reached the predetermined location between the peristalticpump assembly 16 and the sample collector 18. At this point in time, theflow measurement and control circuit 12 may, in accordance with somestandard programs, purge the conduit and redraw the fluid 24, or inothers, continue to pump to draw a sample and deposit the sample into acontainer.

When the location of the fluid 24 reaches the sensor after a purge cycleif there is one, the flow measurement and control circuit 12 causes apredetermined amount of fluid to be deposited in a container within thesample collector 18, and in some embodiments, the sample collector mayinclude a distributor or may move containers to deposit sample insuccession during different pumping cycles. The number of pumping cyclesrequired is determined in the preferred embodiment by a computer look-uptable containing data based on trial measurements with conduits of thesame inner diameter to determine the number of pumping cycles requiredfor a given volume once the interface has been sensed in a manner to bedescribed in greater detail hereinafter.

The statistical database and look-up tables can be calibrated andcontinuously updated by standard adaptive techniques. More specifically,the amount of sample deposited in containers can be measured and enteredinto the database to update the look-up table by providing a betteraverage base for the variable parameters.

The sensor may sense some initial bursts of liquid prior to a constantcontinuous flow. This happens because the sensor detects an initial flowof liquid but in some circumstances, the fluid 24 may contain airbubbles. The fluid measurement and control circuit 12 counts the numberof cycles of the pump as indicated by the cycle signal generator 11 forthe liquid that flows through a predetermined point and adds thosecycles that are significant to the total liquid pumped into a samplecontainer or to a predetermined point required for a rinse or purgecycle. The counting occurs after the liquid interface reaches thepredetermined point. This permits the pumping system to more preciselymeter liquid into a container.

In FIG. 2, there is shown, in a perspective view, a liquid samplecollector 18, having a generally cylindrical base 93 and a generallycylindrical cover 95 fitted to the base 93. The base 93 includes asample bottle tub 101, a control section 103, and a liquid routing ordistributor section 105, conformably fitting between the sample bottletub 101 and the control section 103, with the distributor section 105and the sample bottle tub 101 each having three different latch keepereyelets mounted thereon, two of which are shown at 111A and 115A,adapted to receive the hooks of a latch. The cover 95 and thedistributor section 105 each have three different latches mountedthereon, two of which are shown at 109A and 113A, each having eyeletsadapted to receive either the hooks of a removable harness by which thesample collector 18 may be suspended in position or may be loweredthrough a manhole, or a harness by which the sample collector 18 may besecured from being tampered with, or which will accept padlocks forsecuring the sample collector 18 from being tampered with.

The base 93 and cover 95 are of tough, chemical resistant plastic withexternal parts that fit tightly together and are latchable in place sothat the entire sample collector 18 is able to withstand corrosiveenvironments and even accidental submersion in a liquid for shortperiods of time.

To latch the cover 95 to the distributor section 105, three stainlesssteel latches, one of which is shown at 109A, are flexibly mounted atone end to the cover 95 at three circumferentially-spaced locations andeach adapted to engage with a corresponding one of three upper latchkeeper on the distributor section 105, one of which is shown at acircumferentially-spaced location 111A on the distributor section 105.Preferably the eyelets and latches should be of stainless steel. A drainis provided at the bottom of the base 93 having an externally threadeddrain spout 301 that may be closed by the gasket 303 and internallythreaded cap 305.

To latch the bottle tub 101 and the liquid routing section 105 together,three lower latches are provided at circumferentially-spaced locationson the distributor section 105, one of which is shown at 113A, and areadapted to engage with corresponding ones of three latching keepers, oneof which is shown at 115A, on the bottle tub 101.

The sample collector 18 is used to collect a plurality of samples of aliquid into a group of different containers across a period of time fromany body of liquid such as from a river, sewage system, process vat orthe like or a single composite sample. Before operation, the containersare loaded into the bottle tub 101, the bottle tub 101, the liquidrouting section 105, and the control section 103 are latched togetherand the cover 95 and control section 103 are latched together.

To operate the sample collector 18, the desired program or programs areinserted into the computer 12, the tubular intake hose 20 (FIG. 1) isinserted into the body of liquid that is to be sampled and the samplecollector is started. In operation, liquid is drawn through the tubularintake hose 20 at timed, flow paced or random intervals and routed toone of the different containers within the bottle tub 101 by the liquidrouting or distributor section 105. A module 202 such as a pH meter,ultrasonic detector bubbler or the like may be inserted as shown at 204and connected for cooperation with the sampler before starting asdescribed hereinafter.

The control section 103 includes a sensor assemby 14, a computer 12, apump assembly 16 and a module section 204 as its principal parts. Thesensor assembly 14, computer 12, pump assembly 16 and the module section204 cooperate together to control the distributor section 105 and thesampler 18. The sensor assembly 14 and pump assembly 16 are housedadjacent to each other near the top of the control section 103. Thesensor section 14 is within the hinged cover 212. A thumb screw 216 canbe removed to open the cover 212 about the hinge 213 and expose thesensor.

The pump assembly 16 encloses the peristaltic pump, rollers and the tubewithin a metal band 220 and a cover 214. The roller paddle axis ofrotation is vertical and an axle ends in the cover 214 at 218 fororbiting of the rollers in a horizontal plane about a vertical axis ofrotation. With this arrangement, easy access is provided to the pump forinsertion and removal of the pump tubing.

To provide flexibility in operation, the module compartment 204 isadapted to receive a plurality of modules that cooperate with thecontrol section 103. One such module 202 is shown having a connector 226adapted to engage a complimentary connector 206 in the modulecompartment 204 for operative connection thereto and having a springbiased detent 207 for engaging a complimentary opening 208 to snap inplace.

In the preferred embodiment, four modules are interchangable in thecompartment 204. They are: (1) a four to 20 mA (milliampere) module thatprovides a connection to receive analogue signals in the range of fourto 20 mA range converts to digital signals and transmit them to thecomputer for storage in the memory of the computer 12; (2) a bubblerthat possibly converts to level, or other parameter, provides air to aprobe, receives pressure signals, converts them to analogue signals,digitizes them and transmits them to the computer 12 for storage in thecomputer, after which the computer 12 may determine flow rate and theamount of flow for purposes of triggering sample taking; (3) a pH meterand temperature sensing module that receives signals from a probeindicating temperature and pH, digitizes and transmits them to thecomputer for storage; and (4) an ultrasonic module that receives depthinformation from an ultrasonic level measuring probe, digitizes it, andtransmits it to the computer for storage in the memory of the computer12 and possible calculation of flow rate and flow for the purpose oftriggering sample taking.

In FIG. 3, there is shown a partly exploded perspective view of thepulse sensor assembly 14 having first and second sections 30 and 32. Thefirst and second sections 30 and 32 fit together to form an enclosurehaving two cylindrical openings extending through it, each of whichreceive and confine a different part of a length of conduit 20. One partof the length of the conduit 20 fits in a first groove 45 which receivesthe conduit 20, with a piezoelectric sensor (not shown in FIG. 3)fitting over it to be strained as the conduit 20 deforms. The conduit 20is looped through the pump and passes in the other direction through asecond cylindrical groove. The two sections are held together byfasteners 34A, 34B.

In FIG. 4, there is shown an exploded perspective view of the secondsection 32 having a housing 35, a piezoelectric sensor 42, a wovenfiberglass protective member 37 and first and second seating inserts 38Aand 38B. The housing 35 of the second section 32 receives the protectivemember 37, piezoelectric sensor 42, and inserts 38A and 38B and forms aunit fastened together with first section 30 (FIG. 3) to hold theconduit 20 (FIGS. 1 and 2) against motion caused by the pump 16 (FIG. 1)during its rotation against the conduit 20 and to hold and protect thepiezoelectric sensor 42 against the conduit to sense changes in pressurewithin it caused by action of the pump.

The housing 35 includes: (1) five apertures 33A, 33B, 33C, 33D and 33Esized to receive one end of five fasteners 36A, 36B, 36C, 36D and 36E;(2) four smaller apertures 39A, 39B, 39C and 39D which receive one endof four pins 41A, 41B, 41C and 41D that pass through apertures 43A, 43B,43C and 43D in the piezoelectric sensor 42, and form a part of theholding means for the sensor 42; (3) cylindrical grooves 45 and 47 and asensing aperture 47A through which the conductor 46B passes. With thisarrangement, the housing 35 aids in holding the sensor 42, theprotective member 37 and the inserts 38A and 38B in place. The firstsection 30 (FIG. 3) and second section 32 of the sensor assembly areheld together by thumb screws 34A and 34B (FIG. 3) which engage threadedbores 29A and 29B. The fasteners 36A-36E thread into bosses (not shown)in the inserts 38A and 38B.

The piezoelectric sensor 42 includes: (1) a piezoelectric film 46A whichchanges its electrical characteristics in response to changes in itsstrain and generates an electrical potential; and (2) a conductor 46Bconnected to the film which passes through the second section 32 forelectrical connection to the flow measurement and control circuit 12(FIG. 1) to which it transmits electrical signals indicating changes inthe strain in the piezoelectric film 46A. The piezoelectric film 46Aincludes four apertures 43A-43D passing through it on opposite sides ofthe groove 45 to form a portion of a holding or clamping means holdingthe piezoelectric film 46A in place against the conduit 20 (FIG. 1 and3).

During installation of the tubing 20 (FIG. 3), the piezoelectric film46A is pre-stretched by the force of the tubing against thepiezoelectric film 46A, the edges of which are held by the pins 41A-41D.The contact between the tubing 20 and the piezoelectric film 46A ismaintained intimate by the bias from the stretching of the piezoelectricfilm 46A and extends over a sufficient surface area with sufficientpressure between the film and the tube 20 to supply adequate couplingfor a reliable transfer of force. The coupling is adequate to cause thefilm to generate repeatable electrical signals in response to a range offorces transferred to it. In the preferred embodiment the area ofcontact between the piezoelectric film 46A and the tube 20 is 1/4 squareinch but can be as small as 1/16 square inch.

To protect the piezoelectric sensor 42, a woven fiberglass member 37with a Teflon (trademark by Du Pont de Nemours, E. I. and Co.,Wilmington, Del. 19898 for tetrafluoroethylene fluorocarbon polymers)coating on its top and bottom surfaces and fused over it to form astrong flexible member. It also includes: (1) five apertures alignedwith the five apertures 33A, 33B, 33C, 33D and 33E in the housing 35 toreceive the two bosses in 38A (not shown) and three bosses in 38B (notshown) that the fasteners 36A, 36B, 36C, 36D and 36E are threaded into;(2) an aperture aligned with the aperture 29A in the housing 35 to holdfirst section 30 and housing 35 together; and (3) four apertures 45A-45Daligned with the four smaller apertures 39A, 39B, 39C and 39D to receivefour pins 41A, 41B, 41C and 41D that are also received by apertures 43A,43B, 43C and 43D in the piezoelectric film 46A before being seated inthe inserts 38A and 38B.

To receive and hold one end of the pins 41A-41D, the inserts 38A and 38Bare sized to rest between the protective member 37 and the first section30 (FIG. 3) and includes: (1) an aperture to receive fastener 34A (FIG.3) which passes through it and engages threaded bore 29A; and (2) fourholes 37A-37D in the side facing the protective member 37 to receive oneend of each of the corresponding pins 41A-41D. With this arrangement,the pins 41A-41D hold the film 46A in place on opposite sides of theconduit 20 (FIG. 3) and are in turn held in place by the inserts 38A and38B on one side and the housing 35 on the other.

In FIG. 5, there is shown an elevational sectional view of the secondsection 32 taken through lines 5--5 of FIG. 4 and showing the grooves 45and 47, apertures 29A, 29B, 39B, 39E, 33B, 33C and 33D for seating pinsand holding the first and second sections together. As best shown inthis view, the conduits and piezoelectric sensor may be securely held inthe formed solid rigid housing to receive signals from the pump. Withinthe groove 45 there is an enlarged portion 45E (FIG. 5) to allowexpansion of conduit 20 (FIG. 3) during pulsation. The opening 47A ispotted to avoid wire flexing.

In the preferred embodiment, the enlarged portion 45E of the groove 45is a large enough area to receive the conduit 20 and piezoelectric film46A (FIG. 4) and forms a recess with a depth approximately 1/16 inch. Itis large enough to accommodate expansion of the conduit 20 duringpulsation and the depth should be at least the thickness of the filmplus one one-thousandth of an inch.

In FIG. 6, there is shown a simplified view of the peristaltic pumpassembly 16 and sensor assembly 14. As shown in this view, the sensorassembly 14 is on the inlet side of the peristaltic pump assembly 16 andin one embodiment spaced therefrom. In the preferred embodiment, thedistance between a roller 21 as it contacts tube 20 and the sensorassembly 14 is 3.125 inches and should be less than 18 inches to avoidundue attenuation of the pulses imported through the conduit and liquidfrom the force of pumps to the sensor assembly 14 before being sensed.

Although the embodiment of FIG. 6 shows a sensing assembly 14 spacedfrom the rollers 21 of the pump, it is possible to locate apiezoelectric film in the pump housing positioned to sense therelaxation of the conduit 20 between compression by rollers. Thisresults in a change in strain within the piezoelectric film 46A (notshown in FIG. 6). The change in strain has a different time-amplitudecharacteristic when liquid is in the pump than when it has not yetreached the pump or has passed through the pump.

In FIG. 7, there is shown a simplified perspective view of a sampler 18broken away to show the interior of the bottle compartment 101 anddistributor section 105 having a plurality of sampler containers260A-260K arranged in a ring, a distributor shaft 230, a distributorsupport 262 for hose 20 held by a spring 264 and an adjustable hoseoutlet or nozzle 266 having a downwardly bent nozzle 268 on its end.With this arrangement, the distributor shaft 230 is rotated by adistributor motor from position to position over the containers260A-260K, which are open in the sampling position, and the pump anddistributor deposits samples in them in accordance with a program.

The hose positioner 262 includes a section formed as a split sleeve thatpermits the section 266 to be inserted under it with the split sleeve262 being tightened over it and held in place by any of a plurity ofthumb screws 270. In this manner, the nozzle 268 may be adjusted forradial length from the distributor shaft 230.

A stop member 272 is fastened upwardly to cooperate with a downwardlyextending detent 274. The detent 274 extends downwardly from a baseplate and is adapted to engage the stop member 272 for zeroing thedistributor.

More specifically, the distributor is moved until it reaches the stopmember 274. The pressure against the stop member 274 is sensed bydetecting that the arm no longer moves and the motor is reversed untilthe distributor moves substantially through 360 degrees and engages thestop member 274 again. The travel on both ends of the 360 degree arc ismeasured and this difference is used to establish a zero point. The zeropoint is utilized in a manner to be described hereinafter to enable thecomputer 12 to maintain a record of the position of the distributor atall times. The amount of coasting is recorded and continually averagedat each cycle to more and more closely monitor the position of thedistributor arm by repeated averaging so as to continually improve thethe performance of the system by reducing the number of "hunt" cycles tocorrectly obtain the registration of the nozzle outlet of thedistributor with the location of the containers.

In FIG. 8 there is shown a fragmentary, perspective, exploded view ofthe control section 103 and a portion of the distributor section 105(FIGS. 2 and 7) including the sensor assembly 14 and pump assembly 16with their respective covers 212 and 214 exploded away and thedistributor shaft 230, transmission 232 and optical system 234. As bestshown in this view, the distributor shaft 230 and optical system 234 aredriven in sychronism by a motor 240 to move the distributor fromlocation to location under the control of the computer 12 (FIG. 2).

To control motion of the distributor, the distributor motor 240 drives aworm 244 on its output shaft. Worm 244 engages gear 246, which turns theoptical blocking wheel 250 and worm 248. Optical blocking wheel 250 hasopaque portions and light passing protions. The opaque and light passingportions of wheel 250 alternately pass through and interrupt twoadjacent light paths to alternately block light and pass light throughthe paths.

A first light path is between a first light source 252A and a firstphotosensor 254A and the second light path is between a second lightsource 252B and a second photosensor 254B. When the wheel 250 rotates ina clockwise direction the first light path is cut just before the secondlight path and when the wheel 250 rotates in a counter-clockwisedirection, the second light path is cut just before the first lightpath.

With this arrangement, the sequence of pulses from the photosensors tothe computer indicates the direction of rotation of the distributorshaft. The phase of pulse pairs with the pulse from the firstphotosensor 252A just before the pulse from the second photosensor 252Bindicates the clockwise angle through which the distributor shaft movesand the phase of pulses with the pulse from the second photosensor 252Bjust before the pulse from the first photosensor 252A indicates theangle of turning of the distributor shaft in the counter-clockwisedirection.

After the distributor system has been zeroed and from counting thenumber of pulses and the direction, the distributor outlet 268 (FIG. 7)can be moved to any position in the 360 degree circle. The distributoroutlet 268 can be moved in either direction.

The pump compartment 16 includes the metal band 220 (FIGS. 2 and 7)having a hinge 300 at one end and a hook encompassing a magnet at theother end 280, with the hinge 300 being connectable at one end of thepump housing 16 and the other end 280 having a keeper over which thehook may be pulled to close the pump. The hook has an opening in itcontaining a magnet that interacts with a reed switch positioned nearthe keeper at 282.

With this arrangement, when the magnet 280 is located close to the reedswitch indicating the band 220 is closing the pump section, a circuitfor pump power is also closable and the pump may run. However, when theband is open, the magnet is removed from the reed switch and the powercircuit remains open because the reed switch is not activated by themagnet. This arrangement prevents the motor from operating unless theband is closed. The band may simply be opened by moving the flexiblemember and unhooking its hooked end to gain access to the pump tube foreasy replacement thereof.

Within the pump compartment, is a first raceway 300A for receiving thepump tubing and for cooperation with a complimentary raceway 302 in thetop cover 214 to permit the roller to be orbited along the raceway todepress the tubing without crushing it in a manner to be describedhereinafter.

In FIG. 9, there is shown an exploded perspective view of anotherembodiment of second section 32A similar to the second section 32 ofFIG. 4 except that one end 43 of the piezoelectric sensor 42A extendsdownwardly into a slot and is potted in place. Also, the channels forreceiving the conduit (not shown in FIG. 9) are relatively level and aTeflon hold-down clip for the fiberglass protective member 37A is shownat 41A to prevent the protective member from moving upwardly as the pumphose 20 (FIGS. 1 and 3) is inserted. The unit functions substantially inthe same manner as the sensing unit of which the second section 32 shownin FIG. 4 is a part.

In FIG. 10, there is shown an enlarged perspective view of a rollerassembly 21A similar to the roller assembly 21 of FIG. 6 having ahousing 290, a first end roller 292 on one end of the rotary housing 290and a second end roller 294 on the other end of the housing, wherein thehousing 290 may be rotated about its axis at 291 to orbit the rollers292 and 294 against the peristaltic pump tube 20 (FIGS. 1 and 3). Inthis embodiment, two retaining posts 296 and 298 are provided extendingperpendicular from the longitudinal plane of the frame 290 and therotational axis of the rollers 292 and 294. The retaining posts 296 and298 are adjacent to each other and adapted to straddle the peristalticpump tube 20 (FIGS. 1 and 3).

The assemblies 296 and 298 are intended to prevent the tube from movingfrom position to position laterally with respect to the rollers as itstretches from use, and for this purpose, include bottom members 296Aand 298A respectively supporting the post 296 and 298 in place andhaving at their upper end rotary rollers 296B and 298B respectively torotate with respect to the peristaltic pump tube 20 passing betweenthem.

In FIG. 11, there is shown a simplified fragmentary plan view of thepump section 16 (FIGS. 7 and 8) and a portion of the sensing section 14(FIGS. 7 and 8) having the peristaltic tube 20 and an embodiment ofroller assembly 21A. The peristaltic tube 20 includes first and secondcircumferentially extending bands surrounding the tube 300 and 302,slightly elevated beyond the outer wall of the tube, such as for exampleby 1/16 inch, and approximately 1/2 inch wide. These raised bands fitconformably within corresponding depressions in the outer surface of thelower member of the sensing unit to enable proper placement of the hose20 within the pump and sensing unit. It is also possible to use unraisedcolored bands to aid in the placement of the tube although theindentation and corresponding circumferential bands provide grippingaction in addition to ease of placement of the tube.

The roller assembly 21A includes the shaft 304 driven by the pump motorfor rotating the rollers 294 and 292 to compress the tube 20 and thuspump fluid upwardly through the sensor. The post 296 is shown on oneside of the tube 20 to maintain it in alignment. This post and itscompanion post on the opposite side of the tube continually rotate aboutthe axis of rotation of the shaft 304 as the rollers are orbited tocontinually re-align the tube and prevent it from lateral movement.

In FIG. 12, there is shown a fragmentary schematic view of anotherembodiment of pump chamber 16B having a roller assembly 21B, aperistaltic tube 20, a pump chamber surface 310, a raceway 312 in thepump cover 214, a roller 294 and a roller frame 290A. In thisembodiment, the cover 214 closes downwardly so that the raceway 312engages the edge 310 providing two surfaces spaced so that when theperistaltic pump tube 20 is completely compressed by the roller 294, theside portions of the roller do not rest on the raceway edges. In thisembodiment, the roller may be held by a spring biased member in theroller frame 290 but this is not required. The spring rollers allow thetubing walls 20 to be completely compressed but not crushed. The raceway312 acts as a tube guide to not allow any lateral movement of the tube20 within the pump.

In FIG. 13, there is shown a schematic fragmentary view of anotherembodiment of pump chamber 16C similar to the pump chamber 16B of FIG.12 but including a roller formed with three independent roller parts294A, 294B and 294C. The central roller 294B is sized to fit over thetube 20 whereas the rollers 294A and 294C engage the edges of the coverand base of the chamber so as to not allow roller 294B to crush thewalls of the tube 20 but only able to completely compress it. They areall mounted on the same shaft so that the side rollers, which rollindependently, hold the roller 294B from crushing the walls of the tube20.

In FIG. 14, there is shown a schematic diagram of one of the modules 202(FIG. 2) that cooperates with the control panel 103. This module is abubbler module shown generally at 202A connected to a desiccant chamber324, an air inlet 326, a hydrophobic filter 322 and a bubbler line 320.The module 202A fits within the compartment 204 (FIG. 2) in the mannerdescribed above and is connected to a bubbler probe through the line 220to transmit air at a pressure equal to the hydrostatic pressure of thebubbler probe and thus to transmit pressure back to line 320 equal tothe hydrostatic pressure to provide an indication of the depth of theprobe. The air inlet 326 provides air at a reference atmosphericpressure, which is dried in the desiccant chamber 324 and filtered inthe filter 322 before being connected to communicate with the module202A.

The module 202A includes an air tank 328, a manifold 330, a pump 332, adifferential pressure transducer 334, a filter 336, a check valve 338, ableed oriface or restrictor 340 and a 1.4 psi (pounds per square inch)differential pressure switch 344. The air inlet line communicating withthe hydrophobic filter 322 communicates with a second hydrophobic filter336 to provide an air line into the manifold 330 at substantiallyatmospheric pressure. This line is also connected to the pump inlet 332,the outlet of which communicates through the check valve 338 to the tank328 so as to be capable of pumping air into the tank 328 and thuspressurizing it. The check valve 338 prevents back flow through the pump332.

The 0.004 inch diameter bleed oriface 340 communicates with the airinlet line to the manifold 330, connecting with the filter 336 and theair inlet of the pump 332 within the manifold 330.

Within the manifold, the air inlet line from the bleed oriface 340 alsocommunicates with a line 348 to provide a reference pressure to thedifferential pressure transducer 334. The bubbler communicates with thedifferential pressure transducer 334 through the air line 346 from themanifold 330 to transmit a head of pressure to the transducer equal tothe depth of the liquid. The bubbler line 320 carrying the hydrostaticpressure communicates with the manifold and with the 1.5 psidifferential switch 344 to transmit pressure to both of them. The 1.5psi differential pressure switch also communicates with the manifold.

The manifold 330 includes within it a bleeder 350, a three-way valve356, a normally closed two-way valve 354, and a bubbler oriface 352which is 0.001 inches in diameter. With this arrangement, within themanifold 330, the bubbler line 320 transmits pressure to thedifferential pressure switch 344 as does the outlet from the tank 328 sothat when the pressure from the outlet of the tank 328 differs from thepressure from the line 322 by 1.5 psi or less than 1.5 psi indicating alow flow rate, the switch 344 energizes the pump to recharge the tank328. The bleeder oriface 350 permits the escape of air from the manifoldat a low rate to conserve power. The two-way valve 354 allows apreprogrammed bypass around the orifice 352 to clear debris from thesensor attached to conduit 320. Air from the air inlet 326 istransmitted through the switch 356 in one position of the three-wayvalve 356 to apply zero drift pressure to transducer 344 and thus torezero the electronics. In the other position of the three-way valve,air from the bubbler line 320 at hydrostatic pressure is transmitted tothe differential pressure transducer.

In the measuring position, the differential pressure transducer 344transmits an electrical signal on conductor 360 to a analog to digitalconvertor at the interface with the computer 12 for development of andthe storage of a digital signal indicating the depth of the flow streambeing sampled.

In FIG. 15, there is shown a schematic diagram illustrating a leveldetector 403 for a container 400 receiving liquid from a distributorhose 20 within a distributor arm. The container 400 may be one ofseveral containers or a central single container coming directly fromthe tubing 20 through a central guide without the use of the distributorarm. The container includes a float 402 mounted within a cage 404fastened to the top of the container. The float 402 includes anupstanding post with a magnet 406 on the top. The magnet 406 may bedetected by a reed switch 408 mounted to the top of the bottle tub 93(FIG. 18).

This arrangement provides three methods of detecting overflow of acontainer. The first method is by the float 402 rising within the cage404 as the liquid rises near the outlet of the container 400 until it isin proximity with the reed switch 408. The activation of the reed switchprovides a signal indicating a near over flow condition. In analternative embodiment, the mouth of the conduit 20 is adjacent to thecontainer opening. When the liquid rises above the outlet from theconduit 20, a purging cycle which would normally pump air out of thetube in a direction away from the container, pulls liquid from thecontainer, thus causing transmission of pulses from the pump duringpurge operations. These pulses are counted, then compared with a recenthistory of purge counts threshold, to detect an over-flow condition. Athird method is to sense the increased pulses when the drawn liquidmoves a sufficient distance toward the peristaltic pump.

In drawing samples from a stream for depositing into sample containers,it is desirable that water be sampled or pulled from the stream at arate of two feet per second which is the typical speed of liquid in asewer. However, it is difficult to do this under a relatively long headof pressure with a peristaltic pump because of the inability of the pumpto draw liquid at that rate. This difficulty occurs because, as thespeed of the peristaltic pump is increased under a high head ofpressure, the tube fails to return to its fully expanded position aftera roller compresses it. This limits the amount of force pulling theliquid upwardly because the tube does not expand its complete distance.

In the specification, the terms "coefficient of restoration" and "energyof restoration" are utilized to describe the ability of the tube toreturn to its fully restored position. Energy of restoration is theamount of energy which can be stored by the tube at a given speed of thepump or of liquid being draw through the tube. The coefficient ofrestoration is the fraction of the distance returned by the tube aftercompression at a particular speed and head of pressure. Thus acoefficient of restoration of one indicates that the tube is fullyrestored.

The energy of restoration is a function of the wall thickness of thetube, the modulus of elasticity of the material in the tube and thespeed of compression or the time period between compressions.

To be able to draw liquid at a rate of two feet per second under aminimum head of 20 feet, a silicon tube designated MDF-0215 availablefrom Dow Corning Corporation, Midland, Mich. 48686-0994 with a wallthickness of 0.145 inches with an internal diameter of 0.375 inches anda post cure with a sufficient restoration of one at 300 rpm (revolutionsper minute) is used. This combination can pull liquid against a head of23 feet at a rate of two feet per second. Generally, different materialsand thickness may be selected by trial and error to obtain a restorationfactor of one at the desired rpm, head of pressure and rate of drawingthe liquid, which has as a standard two feet per second. Post curingmeans curing at a slightly elevated temperature until the desiredmodulus of elasticity is obtained to provide the desired restorationcoefficient. The modules of elasticity is stable at this point and willnot change by more than ten percent.

In FIG. 16, there is shown a block diagram of the flow measurement andcontrol circuit 12 having a microprocessor 62 and an interface assemblyshown generally at 60. In the preferred embodiment, the microprocessor62 is a Model Z8S180 sold by Zilog and includes a look-up table memory63 as well as the normal logic components 65 forming the microprocessorcentral control. The look-up table memory 63 is accessed by the centralcontrol to look-up values corresponding to certain numbers of cycles ofthe pump 16 (FIG. 1) applied to it through the pump interface 60 througha conductor 77.

The interface 60 includes a sensor interface 70, connected to the pulsesensor assembly 14 (FIG. 1) through a conductor 46 and to themicroprocessor 62 through a conductor 67, a keyboard 72 for enteringdata into the microprocessor 62 through a cable 72A, a pump interface 74for transmitting start and stop signals through a cable 75 to theperistaltic pump assembly 16 (FIG. 1) in response to signals from themicroprocessor 62 through a conductor 77 and a sample collectorinterface 76 receiving signals from the sample collector 18 (FIG. 1) ona conductor 79 and transmitting signals to the sample collector 18through a conductor 81. The sample collector interface 76 transmitsignals to the microprocessor 62 through a conductor 82 and receivessignals through a conductor 84.

With this arrangement, the microprocessor receives indications ofcycling of the peristaltic pump assembly 16 when the water interfacereaches a predetermined location, counts those cycles and uses the countfor other control functions such as moving bottles in the samplecollector, stopping and reversing the pump and restarting the pump foranother cycle, starting timing for the intervals between drawing samplesand the like.

In the preferred embodiment, once the pumping system has determined thatliquid is flowing from the amplitude of measured pulses, sensed cyclesof the pump are counted during the time the amplitude of the strainpulses is above the threshold.

In FIG. 17, there is shown a block diagram of the sensor interface 70having an input low-pass filter and pulse shaping section 71 and anoutput section 73. The input low-pass filter 71 is a National MF6 set tohave a 45 hertz cut-off and a 0.5 volt threshold. The output section 73shapes the input pulses to a square wave and discriminates againstpulses having a time duration less than a predetermined time set by theRC circuit 73A. However, any suitable interface may be used.

In FIG. 18, there is shown a block diagram of the main subprograms ofthe program that controls the pumping system 10 (FIG. 1) including astandby mode subprogram 140 and a plurality of operating subprogramsshowns generally at 141. When the pumping system 10 is turned on andafter completion of each of the operating subprograms shown collectivelyat 141, the program automatically goes to the standby mode 140. The userthen enters the command to go to any of the other subprograms of thepumping system 10 (FIG. 1). The main subprograms shown in the group 141include: (1) configure sequence 150; (2) program sequence 190; (3)manual controls 200; (4) run program 210; and (5) program and runtimereview 220. Many programs used in the operation of a pumping system arenot related to the invention and are standard for equipment of thistype. These programs are not described in any detail herein. However,the programs related to the invention are described in flow diagramform.

Before starting the pump, the user may enter data to set up the pumpingsystem 10 (FIG. 1) so that it will. operate to the user's specificneeds. If the user does not wish to change the settings from the mostrecent run, then he would not use these programs. This user-definedinformation may be entered in the configure sequence 150 and the programsequence 190. The configure sequence 150 is used to enter certain datasuch as bottle count and size, correct time and suction lineinformation. Most of the data entered in the configure sequence 150 areof a type that do not change often. The program sequence 190 is used toenter data for the specifics of the sampling routine such as samplevolume, frequency and distribution method.

The run program sequence 210 runs the sampling routine using the dataprogrammed in the configure sequence 150 and program sequence 190 andthe program and runtime review 220 displays the program settings andsampling routine results. The manual controls program sequence 200sequences through steps that operate the pump and distributor inresponse to manually entered instructions by the operator.

In FIG. 19, there is shown a block diagram of the main parts of theconfigure sequence 150 (FIG. 18). The parts include: (1) tubing lifeindicator subsequence 154; (2) liquid detector subsequence 162; (3)suction line subsequence 172; and (4) bottle subsequence 180. Thesubsequences together provide data points into the system forconfiguring the pumping system 10 (FIG. 1).

In FIG. 20, there is shown a flow diagram of the tubing life indicatorsubsequence 154 (FIG. 19) of the configure sequence 150. (FIGS. 18 and19). The tubing life indicator subsequence 154 monitors usage of thetubing 20 by keeping track of how many cycles the pump has made againstthe tubing 20 in any direction since its last replacement and warns theuser that the tubing 20 should be replaced. Included in the tubing lifeindicator subsequence 154 are: (1) a pump counter subsequence at 156;(2) a reset pump counter subsequence at 158; and (3) a warning trippoint subsequence at 160.

The total pump strokes (12 for each revolution of the pump) and thepoint at which the counter warns the user that it is time to change thetubing 20 are displayed to the user at 156. The range of pump counts forthe life of the tubing 20 is usually between 50,000 and 2 million pumpcounts. If the tubing 20 has been replaced, the user would indicate yesin the reset pump counter subsequence 158 to reset the pump countersubsequence 156. The user-defined warning trip point is entered insubsequence 160. While the pump is pumping, the total pump counts areupdated in a counter and compared to the user-defined count. When theupdate count exceeds the user-defined count, a warning is given.

In FIG. 21, there is shown a flow diagram of the options for the liquiddetector subsequence 162 (FIG. 19) of the configure sequence 150 (FIGS.18 and 19). The liquid detector subsequence 162 controls the liquiddetector and related settings and how many times it will be used todetect liquid. The options for the liquid detector subsequence 162include: (1) a rinse cycle subsequence 166; (2) a manual headsubsequence 168; and (3) a retry subsequence 170.

The head is entered in the programming sequence 190 (FIG. 18) ordetermined by the number of pump counts to liquid.

To detect the liquid either in the rinse cycle, or during collection ofthe sample, then the program requests the user to specify: (1) thenumber of rinse cycles in the rinse subsequence 166; (2) whether a headwill be entered manually in the manual head subsequence 168; and (3) theamount of retries in the retry subsequence 170. The retry subsequence170 controls the amount of retries for both the rinse cycles and theactual collection of sample if no liquid is detected during eitherprocess.

In FIG. 22, there is shown a flow diagram of the suction linesubsequence 172 (FIG. 19) of the configure sequence 150 (FIGS. 18 and19). The suction line subsequence 172 is used to gather informationconcerning the suction line, generates the look-up tables and sets thenumber of post-purge counts. The subsequences in this program are: (1)the inner diameter subsequence 174; (2) the material subsequence 176;and (3) the length subsequence 178.

In the preferred embodiment, the inner diameter of the suction lineentered in the subsequence 174 is entered in inches such as one-quarterinch or three-eighths of an inch, the choice of suction line entered inthe material subsequence 176 is either vinyl or Teflon and the length ofthe suction line entered in the length subsequence 178 can be betweenthree and ninety-nine feet.

In FIG. 23, there is shown a flow diagram of the bottle subsequence 180(FIG. 19) of the configure sequence 150 (FIGS. 18 and 19). The bottlesubsequence 180 is used to set maximum sampling volumes and provideinformation to the distributor movement routine.

Two of the subsequences included in the bottle subsequence 180 arebottle number subsequence 182 and bottle volume subsequence 184. Thebottle number subsequence 180 is used to enter the amount of bottles inthe base and the bottle volume subsequence 184 is used to enter themaximum volume of liquid to be inserted into each bottle.

In FIG. 24, there is shown a flow diagram of portions of the programsequence 190 (FIG. 18). The program sequence 190 is for enteringspecifics of a sampling routine which include: (1) the bottles persample subsequence 192; (2) the sample volume subsequence 194; and (3)the head subsequence at 196. The number of bottles per sample is enteredin the sample subsequence 192 and the amount of sample to be distributedinto each bottle is entered in the sample volume subsequence 194.

To ensure a more accurate calculation of the pump count maximum, thesuction head is entered in the head subsequence 196. The suction head isused to supply information supporting the program operation in theliquid detector subsequence 162 or the user indicated in the headsubsequence 168 that a head would be manually entered (FIG. 21). In thepreferred embodiment, the user can enter a minimum volume of sample of10 milliliters and a minimum suction head of one foot.

In FIG. 25, there is shown a flow diagram of a portion of the runprogram sequence 210 for drawing and distributing a sample in accordancewith an embodiment of the invention. The run program sequence 210includes: (1) the series of steps 92 relating to starting the pump; (2)the rinse routine 100; (3) the series of steps 108 relating to drawing asample; (4) the series of steps 114 relating to distributing the sample;(5) the series of steps 122 relating to storage of the samplinginformation; and (6) the step 128 of retrying a rinse routine or pumpsample routine.

The series of steps 92 relating to starting the pump include the step 94of receiving the sample command, the step 96 of calculating the maximumpump count and the pre-sample purge step 98. After the sample command 94has been received, a maximum pump count is calculated based on the headentered in the head subsequence 196 (FIG. 24) or the head from theprevious sample if no head was entered. Only one value for the head isused to calculate the maximum pump counts and is used throughout theprogram segment. The pre-sample purge command 98 is then performed toclear the strainer of any debris which may have collected since the lastsample was taken.

After the pre-sample purge is completed, the rinse routine 100 isactivated which includes the step 102 to determine if a rinse should beperformed or if a second or third rinse should occur. Rinse routineshave already been preprogrammed by the user in the rinse subsequence 166(FIG. 21). If a rinse is programmed, the liquid is pumped forward in thestep 104 until a predetermined amount of liquid is detected in step 107and the liquid is purged in the step 106.

If the predetermined amount of rinse liquid is detected as havingreached its destination, the rinse routine 100 is begun again asindicated at 102. If another rinse routine is remaining, the liquid ispumped forward at 104 and the remaining steps of the rinse routine arecarried out. The rinse routine 100 is repeated until there are nofurther rinses. When the rinses are complete, the series of steps 108relating to drawing a sample continues with the pump sample routine 110and the step 112 of detecting the liquid.

If no liquid was detected during the rinse routine 100 in the step 107or the step 112 of the series of steps 108, the program in the step 128accesses the retry subsequence 170 of the liquid detector subsequence162 (FIG. 11) to find out if it should retry pumping sample beforeshutting down. If the user entered any retries, and the total amount ofretries has not been met, the program returns to the pre-sample purge 98and starts the rinse routine 100.

If all of the retries have been made or if no retries were programmed,the controller performs a post sample purge at 123, stores the samplinginformation at 124 and returns to the calling routine at 126 of thesteps 122.

If a rinse routine 100 was not programmed, the steps 104, 106 and 107are skipped and the program goes directly to drawing a sample at 110 anddetermines if liquid is detected at 112. The pump sample routine 110 isthe actual process of drawing and measuring the sample and will be laterdescribed in more detail.

When it is indicated at 112 that liquid was detected, the series ofsteps 114 relating to distributing a sample is performed. The first stepof the series of steps 114 is the step 116 of determining if sample isto be inputted into one or more bottles. If only one bottle will befilled, a user-defined amount of sample is then emptied into the bottle,a post sample purge is performed at 123, the sampling information isstored at 124, and the program returns to the calling routine at 126 inthe series of steps 122.

If there is more than one bottle to be filled, a short purge 118 is madeto back the liquid up so that it can detect a second user-defined amountof sample and the the distributor is moved to the next sample bottle at120.

The program segment 210 then returns to the pump sample routine 110until data is received at 112 that the user-defined amount of liquid isdetected. The program checks whether there is more than one bottle leftto fill at 116 and then empties the sample into a sample bottle. If moresample is needed, the remaining steps, 118 of purging the sample and 120of moving the distributor to the next bottle are repeated again. Thesteps of emptying the sample into the bottle at 116, purging the liquidat 118 and moving the distributor at 120 are repeated until it isindicated at 116 that no more sample will be distributed. When no moresample is needed, a post sample purge is performed at 123, the samplinginformation is stored at 124, and the program returns to the callingroutine at 126 in the series of steps 122.

In FIG. 26, there is shown a flow diagram of the pump sample routine 110of the program segment 210 (FIG. 25) for drawing and distributing asample. This routine is the actual pumping of the sample to collect apredetermined amount of liquid in a sample bottle. The pump sampleroutine 110 includes: (1) the series of steps 131 relating to thebeginning stages of pumping; (2) the series of steps 139 related toobtaining the water count; (3) the step 151 of saving information thatno liquid was detected; and (4) the series of steps 153 of stopping thepump.

In the series of steps 131, a pump sample command is received at 137 andthe sample is pumped upstream through the tube 20 (FIGS. 1, 3 and 6).The sample is then continually pumped and the program waits for a pumpcount change at 133. The maximum pump count was predetermined based onthe head of the previous sample or measured by the user and entered intothe program before the user began the pump (not shown) in the configuresequence 150 (FIG. 18).

The program 110 then goes through a series of steps at 139 starting withdetermining if the maximum pump count has been exceeded in the step 161.If the maximum pump count has been exceeded, the program will save theinformation indicating that no liquid was detected at 151 and proceed tothe series of steps 153 of stopping the pump. During shutdown of thepump, the program shuts the pump off at 155 and returns to the callingroutine at 157.

If the maximum pump count has not been exceeded at 161, it is thendetermined whether a good water count was found at 143. The programdetermines if a water count is received so near to the beginning of asample drawing run as to indicate an error. This can occur in the firstfew cycles such as for example four cycles of the pump. After apredetermined number of cycles of the pump, this type of error tends notto occur. In the preferred embodiment, the pump must have counted atleast 50 counts before the count is considered good. If it was not agood water count, the program: (1) returns to waiting for the pump countat 133; and (2) maintains in memory the amount of water counts alreadyreceived and adds a new water count to the previously received watercounts.

If it was a good water count, it is then determined if a new maximumamount of water counts should be calculated at 145. If a new maximumshould be made, the program calculates a new maximum water count at 149,using the head from the previous sample or the head defined by the userin the head subsequence 196 (FIG. 24), and then decides at 147 if thesample water count is the correct amount. If not enough sample waspumped, the program returns to wait for the pump count at 133 and pumpsmore liquid until it has pumped a predetermined amount of pump countsand continues with the series of steps 139 starting at 161 to determineif the maximum count was exceeded. If the pump did receive a correctwater count, it is recorded in memory at 159 that the sample volume wasdelivered correctly and proceeds with the series of steps 153 ofshutting down the pump at 155 and returning to the calling routine at157.

If it is not necessary to calculate the maximum water count, then theprogram skips the step 149 and determines at this point if it is acorrect water count at 147, records that the sample volume was deliveredcorrectly at 159 and proceeds with the series of steps 153 of shuttingoff the pump at 155 and returning to the calling routines at 157.

When the program returns to the calling routine at 157, the memory isaccessed to find out if the liquid was detected at 112 (FIG. 25) and ifit was not, the program would advance to the program at 128 to access170 of the options for the liquid detector control 162 (FIG. 19) of theconfigure sequence 150 to find out if it should retry pumping samplebefore shutting down. If the user entered any retries, and the totalamount of retries has not been met, then the program returns to purgingthe pre-sample at 98 and continuing with the rinse routine 100 (FIG.25).

In FIG. 27, there is shown a flow diagram of the program and run reviewsequence 221 (FIG. 18). The program and run review sequence 221 is usedto check program setting or sampling routine results. The subsequencesincluded are the pump tubing warning subsequence 225 and the sampleinformation for the last sample routine subsequence 223.

Each time the pump count maximum for replacing the tubing is exceeded,the pump tubing warning message at 225 is displayed. The threshold forthe pump count maximum has been user-defined in the tubing lifeindicator control 154 at 156 (FIG. 20) before beginning the pump. If theuser does not enter a new threshold, the threshold from the previoussampling process will be used.

After each sample gathering process, certain information is stored inmemory for future use at 223. Included are: (1) if the sample processwas performed and no liquid was detected at 227; (2) the time and dateat 229; and (3) the number of pump counts before liquid was detected at231 and the amount of time for the entire pump cycle. The number ofcounts before liquid was detected at 231 is used to calculate the headat 149 (FIG. 26).

In FIG. 28, there is shown a block diagram of another embodiment oftubing life indicator circuit 154A for providing a signal after apredetermined number of strokes of roller against the tube 20 (FIGS. 1,3 and 6) in the peristaltic pump assembly 16 (FIG. 1), having the cyclesignal generator 11, a counter 241, a switch 247, a manually resettableswitch 243 and a warning light 253. The counter 241 is directlyconnected to the conductor 13 to receive all counts regardless ofdirection and having an output set at a predetermined number of countsconnected to the resettable switch 243 to actuate the switch at thepredetermined number of counts and thus energize the warning light towhich it is connected.

With this arrangement, the operator may set the counter 241 at a countthat indicates the tube 20 (FIGS. 1, 3 and 6) should be replaced. Whenthe number of pulses from the cycle signal generator 11 reaches thepreset number, the counter 241 supplies a signal to the resettableswitch 243 which applies a signal from the source of voltage 255 to thewarning light 253. The resettable switch 243 can be manaully reset whenthe tube is changed and it resets the counter 241 and disconnects thepower 255 from the warning light 253.

To permit a hardware determination of the direction of rotation, theswitch 247 receives pulses from the conductor 13 and a direction signalfrom the cycle signal generator 11 to switch from one of the two outputconductors 249 or 251 to the other so that pulses representing thenumber cycles in each direction can be determined. This function canalso be performed in software.

In FIG. 29, there is shown a functional flow diagram of the program forpositioning the distributor arm including the step 452 of getting arequest to deposit a sample at a particular location, calibrating thesystem, or updating the position indication of the distributor arm. Withthis arrangement, the position of the distributor arm is continuallyupdated to ensure that any movement of the arm between intentional movesis tracked. A full rotation of the distributor arm results in 1200 statechanges of the optical interrupters described in FIG. 18.

To calibrate the distributor arm, the step 454 of calibrating includesthe steps 460 of moving to stop past the last bottle, the step 462 ofmoving to stop past the first bottle and calculating the total armflexure, the step 464 of obtaining the time to go from bottle five tobottle one of the 24 bottle base as shown in step 464, the step 466 ofgetting the time to go from bottle 20 to bottle 24 of the 24 bottle baseas shown in step 466, the step 468 of assigning a portion of the totalarm flexure to the bottle one side, and the step 470 of moving to bottleone in the order stated. In this manner, a measure is taken of the airat the stop positions caused by flexing of the stop member 272 againstthe stop 274 (FIG. 7) at bottle positions one and the last bottleposition.

The step 456 of going to a bottle includes the step 472 of calculatingthe target position which factors in expected coast and mechanical play,the step 474 of moving the distributor arm through the required numberof change of states as indicated by the optical interrupter, followed bythe step 476 of hunting for the correct position necessary followed bythe step 478 of updating the coast amount which includes 70 percent ofthe old value and 3.0 percent of the new value. The step of hunting forthe correct position relates to the ability to detect overshooting bydetecting a greater number of pulses than the desired positionindicates. If the distributor has been moved, the position must beupdated from the information indicating its current position.

The control module 103 initiates all communications through the computer12 with the modules 202 (FIG. 2). The identification of the module isstored in memory. The modules take readings and convert the readings toengineering units. They respond to requests made by the control module103 (FIG. 2).

To perform random sampling, the program run time is entered in hours andminutes at the keyboard. The number of samples to be taken during therun time is entered into the keyboard for a one bottle configuration,but the computer program calculates the number of samples from thedistribution information for multiple bottle configurations. The programstart time is entered as a delay past the run request or clock time andday of the week at the keyboard.

At the time of running, a set of random numbers is generated. Theserandom numbers are scaled so that the sum of the resulting set of timeintervals equals the program run time. Specific clock times are thencalculated from the random intervals. While the program is running,samples are taken as each of the random clock time occurs at theposition indicated by the generated number. The sample bottles fordepositing can be obtained by inquiring at memory. Moreover, thesoftware can be drawing and inserting samples into containers inaccordance with one program and nontheless simultaneously follow atleast one other sampling program. The other program or programs may betriggered during the execution of the first to start program, such asfor example, by the detection of a preprogrammed value of pH or flowrate.

During sampling, the controller runs the pump in reverse to purge theintake line. When configured for one bottle, the controller keeps trackof how long the liquid presence signal exists while doing itspost-sample purge. This time is indicated by pulses measured by thesensor. If this time measured in pump counts is greater than or equal toa full-threshold, a bottle-full condition is declared. If the count isless than the full-threshold an average of the most recent five readingsis found.

At the program run time, the full-threshold is initialized to 200 (largeenough to eliminate false bottom-full indications). For each consecutivesample, the full-threshold is set to the average as calculated aboveplus a pad of 20. The pad value of 20 counts (approximately 20 ml) isadded to prevent a premature declaration of a bottle-full condition.Because of variations in sampling conditions, a minimum sample volume ofapproximately 40 ml is required for this indicator to work reliably.

From the above description, it can be understood that the pumping systemof this invention has several advantages, such as for example: (1) itpermits higher pumping velocities under high head conditions withperistaltic pumps; (2) it provides longer life to peristaltic pumptubes; (3) it increases the life of tubes and reduces lateral movement;(4) it permits more precise positioning of the distributor outlet port;(5) it permits easy attachment of modules for cooperation with thesampler; (6) it permits safe and easy access to the pump tube forreplacement thereof; and (7) it provides a security system to avoidtampering with samples.

Although a preferred embodiment has been described with someparticularity, many modifications and variations of the preferredembodiment can be made without deviating from the invention. Therefore,it is to be understood that, within the scope of the appended claims,the invention may be practiced other than as specifically described.

What is claimed is:
 1. A peristaltic pump comprising:a motor; aplurality of rollers driven by the motor; means for holding aperistaltic pump tube in the path of said rollers when pumping; meansfor supporting said rollers so as to prevent said rollers fromcompressing said tube more than the thickness of the walls of the tubes;said means for holding said peristaltic pump tube including rotatablemeans moving in conjunction with said rollers to hold said peristalticpump tube in the path of said rollers.
 2. A peristaltic pump inaccordance with claim 1 in which said rollers are mounted to a frame;said means for holding is driven with said frame; and said means forholding includes a pair of perpendicular members which support said tubeas said frame rotates to orbit said rollers and thus prevent said tubefrom moving out of the direct path of said rollers.
 3. A peristalticpump in accordance with claim 1 in which said peristaltic pump includesa housing; said housing including an opening adapted to be closed by aremovable flexible band.
 4. A peristaltic pump in accordance with claim1 further including a sensing means; said peristaltic pump tube having afirst portion entering said peristaltic pump and a second portionleaving said peristaltic pump; and one of said first and second portionsbeing adapted to cooperate with a sensing means to sense the presence ofa fluid in said peristaltic pump.
 5. A peristaltic pump comprising:amotor; a plurality of rollers driven by the motor; means for holding aperistaltic pump tube in the path of said rollers when pumping; meansfor supporting said rollers so as to prevent said rollers fromcompressing said tube more than the thickness of the walls of the tube;said means for holding said peristaltic pump tube including rotatablemeans moving in conjunction with said rollers to hold said peristalticpump tube in the path of said rollers; a frame; said frame being mountedfor rotation in a horizontal plane about a vertical axis of rotationwherein said rollers orbit in a horizontal plane; said peristaltic pumphaving a top, bottom and sides; said top having an openable top coverwherein access to said frame is provided; and one side having anopenable side closure wherein a side entry position is provided.
 6. Aperistaltic pump in accordance with claim 5 in which said cover includesmeans for detecting when the cover is open and means for inhibitingoperation of the motor when the cover is open.
 7. A peristaltic pumpcomprising:a motor; a plurality of rollers driven by the motor; meansfor holding a peristaltic pump tube in the path of said rollers whenpumping; means for supporting said rollers so as to prevent said rollersfrom compressing said tube more than the thickness of the walls of thetube; said means for holding said peristaltic pump tube includingrotatable means moving in conjunction with said rollers to hold saidperistaltic pump tube in the path of said rollers; a rotatable framemeans; said plurality of rollers being mounted to said rotatable framemeans; said plurality of rollers including a central roller adapted toengage said peristaltic pump tube and first and second end rollers onone end of said rotatable frame means; and a tube guide for supportingone side of said tube; said first and second end rollers beingpositioned so that said central roller remains spaced from said tubeguide by at least the distance of the two walls of the peristaltic tubewhile said end rollers rotate on said tube guide.
 8. A peristaltic pumpin accordance with claim 7 in which said central roller is spring biasedtoward said peristaltic tube guide.